Among the various types of prosthetic heart valves which have heretofore been known are certain "stentless" bioprosthetic valves. One example of a stentless bioprosthetic heart valve is described in U.S. Pat. No. 5,197,979 (Quintero, et. al.), the entire disclosure of which is hereby expressly incorporated by reference.
One such stentless bioprosthetic valve is commercially available as the Edwards.RTM. PRIMA.TM. stentless aortic bioprosthesis (Baxter Edwards AG, Spierstrasse 5, GH6048 Horn, Switzerland). This stentless aortic bioprosthesis generally comprises a chemically-tanned porcine aortic heart valve having an adjacent segment of aorta connected thereto. An inflow annulus is defined at the proximal end of the bioprosthesis and an outflow annulus is defined at the distal end thereof. The porcine coronary arteries are cut away from the aortic portion of the bioprosthesis, thereby forming coronary openings in the bioprosthesis. Woven polyester cloth is sewn around the inflow annulus of the bioprosthesis to facilitate suturing of the proximal end of the bioprosthesis to a surgically prepared endogenous aortic valve root of the recipient patient. Thereafter, in cases wherein the entire bioprosthesis is implanted the distal end of the bioprosthesis may be anastomosed to the patient's aorta, and the coronary openings of the bioprosthesis are aligned with, and sutured to, the patient's coronary ostia.
In an alternative implantation procedure, the surgeon may elect to trim or cut away the distal portion of the cylindrical prosthesis body (e.g., that portion above the valve leaflets), and to implant only the proximal portion of the bioprosthesis. In such modified "partial" implantation procedure, it is unnecessary for the surgeon to anastomose that distal end of the distal end of the bioprosthesis and/or the coronary openings to the patient's aorta because such distal portions of the bioprosthesis have been trimmed or cut away prior to its implantation.
The above-described stentless aortic bioprosthesis of U.S. Pat. No. 5,197,979 (Quintero, et al.) was provided with a holding fixture which was attached to the outflow (i.e., distal) end of the bioprosthesis. An elongate handle was connectable to the holding fixture. Such handle was intended to be grasped and manipulated by the surgeon to maneuver the stentless aortic bioprosthesis to its desired implantation position. Certain problems or shortcomings were, however, associated with this holding fixture attached to the outflow (i.e., distal) end of the bioprosthesis. First, the holding fixture was of a configuration which tended to substantially block the outflow end of the prosthetic valve root cylinder, thereby preventing the surgeon from visualizing the valve leaflets from a distal vantage point, during the implantation procedure. Second, because the holding fixture was attached only to the outflow (i.e., distal) end of the stentless bioprosthesis, the exertion of forward pressure against the holding fixture tended to cause the cylindrical body and/or leaflets of the stentless bioprosthesis to compressively deform or buckle, due to the pliable or flexible nature of such stentless bioprosthesis. Such buckling or deformation of the stentless bioprosthesis could be problematic if one were to attempt, in accordance with standard operative technique, to advance the stentless bioprosthesis over a series of pre-placed suture threads which have been passed through the inflow annulus at the inflow (i.e., proximal) end of the bioprosthesis.
In view of the above-described problems associated with the prior art holding fixtures used in conjunction with stentless bioprosthesis, it is desirable to develop an improved holding apparatus which is attachable to the inflow annulus located at the inflow (i.e., proximal) end of the bioprosthesis such that, when proximally directed pressure is exerted against the holding apparatus, such pressure will be transferred through the holding apparatus so as to effect a "pulling" action upon the inflow annulus at the inflow (i.e., proximal) end of the bioprosthesis, rather than a "pushing" action upon the outflow (i.e., distal) end of the bioprosthesis. Furthermore, it is desirable for such improved holding apparatus to be configured and constructed in a manner which does not substantially block the outflow opening at the outflow (i.e., distal) end of the bioprosthesis, thereby allowing the surgeon to clearly view and properly orient the valve leaflets and commissurae of the bioprosthesis during the implantation procedure. Also, it is desirable that the holding apparatus be constructed in a manner which firmly holds the stentless bioprosthesis during any trimming or cutting away of the distal portion of the bioprosthesis, as is sometimes done in the modified or partial implantation technique described hereabove.